Carburetor



J. C. RICHARDSON 2,689,116

CARBURETOR 2 Sheets-Sheeb l nventor W Gttomeg 5' Sept. I14, 1954 FiledMay 8, 1950 Sept 14 -1954 J. c. RICHARDSON 2,689,116

CARBURETOR Filed May 8, 1950 2 Sheets-Sheet 2 UNITED STAT ES?u esulePneu 'rM ortica.,

CARBURETORJ",

JameslvC. Richardson,

N augatuck,` Conn.

Application May'8,-1950, Serial No. 160,645;e,

8 Claims. 1v

This invention relates to fuel-airffmixingrde vices or carburetors forinternall 'combustion fen-1 l gines, and particularly to=carburetors ofthe.type'.y intended to provide a thorough intermixturefbe'- tweena=volatile-uid fuel; suchl as gasolinefand 5 all".

The artof earburetor: building-.hasseenfprog ressirlA many directions;-carburetors "having been$71 developed-:which attempt tov take'care loff'a large number of yarying conditions, and many`oiizvhi'chareueasonably successful. Many-'Yfifnotallof i theseadvancedcarburetors howeverfarevtotally unsuited toordinary-use,- forexampleoni the usualpassenger motor car. kThey -arefnot/only'-excessively'costly initially, but they lals'olre'quire unusual 'skill'for their maintenancewhich Would! make their upkeepltoo*precariousIand'too costly" for ordinary use.

The fact that-developrnentand 'improvement of fcar-buretors forspecialized! purposes'fhasfap parentlyrequiredJmultiplieationfof-inoving par-ts?- controls", nand Iadjustments; seems -to have diverted f1' the-iinvestigationrelating to theimprovement-1- of ordinarycommerciall gasoline engiriefcarbu-lretors-such-as arefused onautomobil'es `from iter-25 proper A channels.One of fthemain considera--A tions inthe design-of l'a carburetorforwide public use-is simplicityfandfreedom', insofarfas *pos-1A sible',from -delicat'e'i-movingparts and'adjuste' ments, withfcorresponding-vreducedfiinitial" cost-"30 and =upkeep expense; Itfhasapparently`ybeen-tlie J general` 'sentiment that` furthensteps in 'fth'is" di.rection'--were impossiblewithout sac-ric'ing fueltf economy 'and -engineperformance# for 1no=-prac 1l tures have appearedin user Presently lused'- commercial y' carbu-retors L are complicated' bythepresence'offuel reservoirs-' or oat chambers :which requirefang-altogether" unrealistic complexity of the-body`1structu`re`for 40casting, not'to men-tion the presence 'of tempera'- A mentali-floatlvalveswhichy can 'cause' severe re hazards -by-their `failure-to operate-fr"eely`.i F`ur=`- ther -complic`ations lintroducing initialjcosts"-asff- WellE as upkeep expenses' include accelerating-145 pumpsfrandrwells; plural Venturis',-- controllable fr mixture altering mea-nsv"-such; as stranglerorl f choke Valves,- automatic *controls-fonsuchchoke valves; and*automa-tic` air -valveswithiorrwitlil e outAinterconnected fuel metering controls It is anrobjectI of'r'theinvention* to proyideaLA carburetor` Which'canlbe operated inconjunction with the conventional 4fuelpumpbut 'Whichis" at the sametime -proofagainst'pressure ejection of fuel due tostickingqfloatValves,n andfhence 55 aowA against the severe rire hazard' occasioned?thereby.J

Itiisfanotherfobject ofthe/invention to -pro-- vde a carburetorWhich-takes full advantageof r modern vfuelf pump characteristicsandwhichre problems.

It' is another 'purposefo :this-invention: topro- Vide a carburetorsuitable for yconventional stockl motor: ,vehiclesf-which: reduces fthemixing of *Afuel andl .airf rto its-simplest terms-whereby ,to reducebothwinitialwcost tand-i maintenance expense'. of

the carbureton'but which' at: the `same time -maintains modernstandardsof performancewithfre gard to reliable starting andidling,smooth1ac+ celerationrand-high power aty full throttle.

the direction!` of y -fuel economy, fas-compared Witl'nl present lstockcarburetorsf-land. the attainment" of Sthisfendw-inr: concert rwith lthesatisfaction of the@fabove-rnentionedipurpose relating. .to si-mplicityand performance.

be prepared Y riorv use byff a i plura1ityv'of-straight drilledpassages, and plugs and inserts-ltherefora` it is another object of theinVentionto-provide 'fa f carburetor r in` which the f--fuel inductionpassage.' Where yfluidy fuel fromA the jets under fuel pump pressure isVatomizcdV to form-a richmixture with a portion of the air prior to itsintroductionn into .the n:.ain-.air stream;a--portionfof said -ai-rpassage forming-:a nonrestrictive 'delecting nozzle for introduction ofthe premix into the mainaairhy stream whilesubstantially,completing theatom= ization of the fuel.

It iszfstill anothern-obfjectv. offthe inventionto ,provide -aycarburetor inv Whichffthe vmoving sopa-V erating parts.- fconsistg-essentially of. f a` ltl'i-rottleY- valve and a main jetmeteringrod/mechanically interconnected; but, --wherein--the propervcond-i-V tions iorfstartingyrunningiat all ordinary speeds, f`accelerating,I andi high lpower or" speed Scan still ,l

be furnished with reasonable accuracy .andl at substantial. economyover. f presentlylused types of carburetors.

Another object offthis invention is the` provision of 1a carburetorwhich providesrel-iable A -fu'rther object of the-invention is the`effectv ing.;` of a marked -improvement ofi carburetion -in f jet orjets communicate with anf-,=au2;iliaryairn U starting performance andstill avoids. the use of a strangler or choke valve and automaticcontrols, and hence eliminates the attendant disadvantages.

Still another object of the invention is the provision of an arrangementof air passages such that a metering of the fluid inlet in consonancewith the throttle movement is all that is necessary to provide adequatemixture control under all conditions.

A further object of the invention is the provision of an air inlet forthe auxiliary air passage so arranged as to draw its air from a sourceprotected by the conventional air filter, and to tap the main air streamin such a way as to measure its velocity and proportion the air velocityin the auxiliary air path thereto.

A further object of the invention is the provision of a parallelarrangement of a main jet and an idling jet so that the fuel issuingfrom either or both will pass into an auxiliary air current in atomizedform prior to the admission of such current to the main air stream.

Another object of the invention is the provision of a carburetor inwhich the main fuel induction nozzle which introduces the fuel mixtureinto the main air stream is a conduit intermediately apertured for fuelescape and in which one end is connected to the auxiliary air passageand the other end communicates with an area of variable reduced pressureat the manifold side of the throttle valve.

Another object of the invention is the provision of a carburetor inwhich the introduction of fuel into the air stream can be effectedwithout the necessity for severe restriction therein, such as venturisand the like which limit the power output of the engine.

A still further object of the invention is the provision of a carburetorhaving any or all of the foregoing features and advantages, and in whichthe average fuel consumption for a given automobile under comparableconditions and for all ordinary types of operation can be reduced atleast twenty percent on the basis of the fuel consumed using a stockcarburetor of the float chamber, plural jet, accelerator pump typecurrently in use and in prime operating condition, and using equivalentperformance adjustments for both types.

Additional features and advantages will hereinafter appear.

In-v the drawings:

Figure 1 is a front elevation of the carburetor of this invention.

Fig. 2 is a side elevation of the device of Fig. 1 taken from the righthand side and looking towards the left.

Fig. 3 is a section taken on line 3--3 of Fig. 2.

Fig. 4 is a section taken on line 4-4 of Figs. 1 and 3.

Fig. 5 is a detailed section taken on line 5-5 of Fig. 1 and 3.

Figs. 6, 7 and 8 are elevations of interchangeable metering membersusable with the carburetors of Figs. 1 to 5 and illustrating severaldifferent suitable profiles.

Fig. 9 is a partial section similar to Fig. 4, but illustrating a modiedform of the mechanical interconnection between the throttle and the fuelmetering means.

The carburetor of this invention comprises a body member ID which ispreferably a single, integral casting. A large passage I2 runningthrough the center of the body I0 constitutes the main air duct andmixing chamber. The upper end of the body I0 is provided with means suchas the seat I4 for receiving the collar I6 of a conventional air filter.The lower end of the body I0 is shaped to provide a sealing flange I8which is bolted to a corresponding flange 20 on the intake manifold. Onone side of the body I0 is an integral enlargement or boss 22 which,together with another integral boss 24 on the opposite side, providesfor most of the principal operating parts and connections to thecarburetor as will hereinafter appear. A small boss 26 near the lowerend of the body I0 provides for the conventional vacuum connection 28communicating with a port 29 opening in the air passage I2 forcontrolling the spark advancing and retarding mechanism.

Throttle valve assembly The carburetor of this invention is essentiallya posterior throttle carburetor, in that the throttle valve is locatedat a position in the main air stream, downstream from the fuel emissionapparatus.

A horizontal bore 3U rotatably carries the throttle shaft 32 whichextends diametrically of the bore I2 at the lower part thereof, andbeyond each side of the casting, and has mounted thereon a butterflyValve 34 of the proper size and shape to open and close the main airpassage I2. An enlarged bore 36 is formed in the lower end 38 of theboss 22 in line with the bore 30 to form a gear housing in a mannerwhich will presently appear, and the same is closed at its outer end bya combined cover plate and bushing member 40. Rotatably mounted on theend of the shaft 32 is a sleeve 42, one end of which is housed in thebore 36 and provided with spur gear teeth 44. The other end has theconfiguration of a worm Wheel 46 and extends through and outside thecover plate 40. Surrounding the outer end of the shaft 32 as well as thesleeve 42 is the drive sleeve 48 integral with an operating lever 50which is connected to a member 52 in the conventional throttle operatinglinkage (Fig. 2). Sleeve 48 is firmly attached to the end of shaft 32 bymeans of a set screw 54 and extends into the central opening of thebushing 40 to rotatably support the shaft 32 and the sleeve 42 therein.A worm` or screw 56 is rotatably mounted in a socket 58 in the sleeve48, meshes with the worm wheel 46 on sleeve 42, and is provided withfriction means 60 for retaining it in adjusted position. The angularrelationship of the operating lever 50 and the attached throttle valve34 to the spur gear 44 is accordingly normally fixed, but it can bereadily adjusted as desired by means of the worm and worm wheelconnection 46, 56 for a purpose which will hereinafter appear. The otherend of shaft 32 is received in a collar 62 which is fixed thereon bymeans of the set screw 64. The collar 62 also carries an arm 66 in whichis threadedly received the stop screw 68 arranged to engage a surface ofthe boss 24 to prevent the valve 34 from closing altogether and foradjusting the size of such minimum opening. The arm 66 is preferablysplit and sprung so as to frictionally retain the screw 68 againstinadvertent rotation due to vibration and the like. Arm 66 also includesa stop surface 6I which cooperates with a portion of the boss 24 toprevent opening of the throttle 34 beyond full open position.

Auzcilary air path Another substantially diametric bore 'I0 crosses 5thgnthroati of; time,Y maimfairepassage I 2f; and @ist formed: in A:thel upperfportiomv'l Zofzithedc Deel2 2 sas` wellies the `lippenportion.of theboss.:24;. ldmiozzle`v tubelrlll iW-ith-oriiicesi 'II'einathefbottom:'thereofxis'sinsertedisfrom:theeopenfendfofizthe boreiin fbossf. 5

245i whichiJ istthenaclosedf .with ia :screw:A cap: @181Preferablyethererareuseveral orifleeseil S-fofr suchl 1.sizesasxostotalapproximately the; internal.,;cross sectioniof:etlietubes14.-.;` Ai smaller-portami iis;

drilledlffin: lthe; upper portion-x12 t offboss 222 l,inn 10 ialignmentrwithnthe -centraliiopening fof;fthe-stubsv 14sandfits-foutenrend =is1.-iclosedl byia :plugnz: At plugged:horizontalraboresi communicates; withiz thezrborernandf'withvanupwardly-1 slopingybore.;l

86 which opens on theointeriorwof-.L-the;mainsairx:l51

passage 1I 2in:the boss integrally :formed thereinizi Firminfafitoned-inttheJoossttianglfextendmg;Aupw-rcllmtherefromeissfunnelsshapedrair- `-ad` mittance memberor.-.ain.sco op5llfwhioh projects;

intiandfpanallelsi.approximately v,the direction,l of N20 f FlaftsfpotControl Passage Anmadditionat passage, Afor:-modifying. `sonf1e-1-` ftheauxiliary'air;:pathiinfa .man-i :describe ,i ,CQnSistStoffafyertica-lw.;

horfiaontal-if bores; 9F12 landt the; communicating;y

plugged, ,unwardlrzfsloping :bore .198,2 the, bereist.: openingfuncn:theymainrairjstream; stammt 5| mr;4 litdlt thsfaothe Side off-thethrottle-Valve 34g; fromthe; noazfletube I\4,zand .the bore 93. vopening-,f10-"\pound;bore c I 4= @which aintersectsfthezbore 5,10

through fthetsclewrcap gli; intoy l tl-1e. interior -of-fY tube '14.

M'cifb-` fuelfiet, metefinassembly' 7and throttle?,

interconnection Afgyerticalnbore; 1I 02` starts; at, the :top-.offboss 22r @mi ommungatesz With-.r the 'enlargedfbores ori gQfl'zhUl-Sgrrlgv 35; Landwirt-h the.v :reduced .bore=f80f1of I.theffauuiliaryrairfrpathri. Anguideobloek millis-`A DI1QSS bore@ggandthe-sime. snugly butv slidably receives;u anpperatingqpin 065,A1so.;located inthe bore I B2i justnabove ithefintersecting .reducedbore 8022 is la pressF-ttlduelijet insert'Y IIJ8.5 A bore 1I IvD-(Figa-g Lhedlpner Dart ofy thevbossv=12`1inter v 55 sects berbere, IMarius-t above the rjet insert I B8: l and? rovided A with; a .fitting:I I2 for connection. tottliggfuelgline I I4-iwl'iichlleads to theconventionultifllflapllmpdnotshownl.. Afbore II5 cony neststhebQjtDm-,of the; gear.. housing 36with the V130 airilasagedxtoxdrainfoany leakage :fuelfrom y thefhousing 56;, 'Iliesrupper -endof i the bore |02r1 islenlargedzandmappedgto; receiveV cap screw I I6wtii closes the upperA end. of the sbore` I 02 Y and retain the',-upnergend fof: fa c-r-coil Y spring.v I I 8,1 the; 65lovvenyl-er-iflg of;l '-whichfzpresses against: the :urgess downwardly atug; I2Itzwhichf fills .the :bore NI B2i` and osirslidab herein; Theplug' e I 2 0 :has anE nligl'alidepelfllllgfplojzectione:I22";whichpassesl:4v

through and normallywlseajis fintheforicetoffjet -70' iin that bore: IIJZ.H below-stifleV i recluced--.A 50' engagement withitheruppemendsoffthe @opel-.attinge pin.-.I 06s Arbore-il 2drparallelto': andf offsetvfroms; thelboreel Ozifopens aat.. .ther-bottom`ofh-vthelowerf section-3B fof rthez-boss 22;'andiisclosedsby-1aiscrewfi= f plug-JI 26. The1bore1l24 'communicates withrthegear-:housingl36:,zand ;by-.a,fslot.':l 2B withfthe bore |02:Slidablymunted'inf-the bore -124 isf-a racks; member, f. I 30e thegtoothedf; portion cfa; whiohriss; meshedgiwiththefspur gear-44.12.Thetupper ^wende;- v'ofi-,the rack member-.VI 30V carries faalateral:projet: tion; I 3 2 .iwhichipassesethrough slot fI 2 8 nndundeI-eliesthe lower endiof theoperatingzroddIIS'zinrp sition to actuate these-mes,Itlwillbefseen .thatrr rotationgoflthe=shaftz32i toproducekopeninganoxnee clockwise rotation as shown in Fig. 4, will revisen` the.racksmemberd 3 Il and feWith it the operating pineA |06 sto thereby:lifztithe:meteringsprojectionn I 22 i and. lprovide 1a. ,slowly f,but,,progressively-:1r en-tfn `larging :annular ,y oriiice cbetweenr :thetjet and-.fsthes meter-ing r projection: CloekWisei-rotation :.oiftlielshaft=32 retractsthe fraek I3IIiandv allowsffspringig: I ILS to:depressrthemeteringmemberd 210,5 |22 andr` operating pinIIlfandfrultimatelyato., returnithemn yto the position shown in Figa/l:HIt shouldalsabe c; noted` that the partsofsboss 2 Zi'mayrbe ssolgaranged if desired,-` that ibore I 0253's in'v .line boreAI2tni'whereupon:lateral: projection: .I 32 wouldn be:dispensedlwith'and operatingrrodi- ;I Ulfcouldii 1either','restuidirectly zon''o1'.A ykbe integrali withrraokr:

member |32. The .-series;soffelementszyjusty den scribed,- includingspur gear .4 Larack .,.I 3U, operati-J;q

ingpinf I 0E. tand metering membersI 2l:provide:fiori.;- mechanicalinterconnection 4between :the fthrottlez, Va-lve :andthe mainfueljet-orificeV riorfa,-fpurposeza. toibe :more :fully described.hereinaftenrr.

Idling iet,

The idling fuert supply `is; provided :byra 1 :comet:

Connection,and.ad:ustment .The Acarburetor is iinstalled Aand`'connected'.aswl shownizwith. the. air filter collar f I6,". thelintake-fz manifold -lange 520,1; the fuel pump output dine# II-4,-fand,the suction yline -2 8; to the..spark-@advance=.- mechanism;whereupon the Ldevice is in condition to -be adjusted 'and used. The adjustrnentsneo-t essary consist merelyvof themain mixture :settingfw andithe idling speed.'

The fscrewfV M4, whichsappears at first'glance totadjusttheidlingrnixture;L is :in fact a 4iix'ed acl-W justment and isseldom-:ifever-touchedi Undei-'w thesfuelfpump pressures normallyusedlth'e :dis-m charge of fuel from'the orifice of valveflIULIIlZi isquite. sufficient: for idling `when thisori-lce-f-isvl extremelysmall'and When=the screw IIUIappears``l to bee tightrdo'wn onvits seatldllnasfshown-inJH Fig. 3.'. This screw construction is'v used as fthemost expedient andsimplest means for obtaining" an l exceedingly minuteorifice which 1 can alsogbe c adjusted-when necessary; Once-aproper'value for the idler jet-forice-settingfor 1a -given :set nfconditions (particularly *for ta given fuer-pump" pressure and motordisplacement) has been determined by experiment and road test, the sameis readily duplicated as follows. The maximum vacuum which can be pulledby a small vacuum pump or air exhausting mechanism is determined, andthe drop in said maximum vacuum which the test orifice produces whenconnected to the intake of the exhausting mechanism is noted. Orificeson other carburetors can be similarly set with great accuracy, then, bymerely connecting them to the intake of the same or a similar airexhausting device and adjusting the orifice to reduce the maximum vacuumby the same amount. If desired, means for locking or sealing thisadjustment, once made, can be provided.

In order to adjust the carburetor all that is required is that theidling speed adjustment screw 68 be set up a few turns to insure thatthe throttle 34 has a substantial opening, that the engine will turnover with moderate speed, and that the operating rod |06 has somesubstantial lifting effect on the metering projection |22 to open themain orifice at jet |08 a significant amount. It is then merely a matterof experimenting with the screw or worm 56, which is capable ofproducing a very slow adjustment in response to large operatingmovements, until the engine turns over most rapidly for the giventhrottle setting as already determined by screw 88. This adjustment ofworm 56 produces the proper orifice at the main fuel jet as determinedby the annular space between jet |08 and metering projection |22, tocorrespond with the predetermined opening of throttle valve 34. Itlikewise produces correspondingly proper orifice openings for all otherconditions of running and openings of the throttle valve 34 provided themetering projection |22 is suitably configured in accordance withprinciples which are set down hereinafter. This adjustment of screw 56,is, of course, maintained by virtue of its coaction with worm wheel 46and friction means 60. Once an accurate mixture setting is thusobtained, the idling speed adjustment screw 68 is merely returned to aposition wherein the idling speed has any appropriate or desired value.With these two basic adjustments properly made, the carburetor of thisinvention will be found to operate properly over the full normal rangeof operating conditions.

Operation-in general As in most plain tube carburetors there is .an airflow in the direction of arrow A, Fig. 3, through passage I2 which iiowis induced by the pumping action ofthe engine cylinders on intakestroke, and the speed for any given loading of this flow is roughlyproportional to the engine speed. At the same time, in the carburetor ofthis invention, there is also produced a parallel or auxiliary aircurrent through the passages 90, 86, 84, 80, '|4, 16. This current isprobably much reduced in speed by virtue of its tortuous and highfriction path, but is also probably essentially proportional to the mainair current A by reason of the position of the inlet funnel 90 which isso directed as to take an approximate reading of the velocity in themain air stream. The speed of the air current through the auxiliary pathis, however, probably sufficiently reduced that the depression effectthereof on the liquid fuel jets |08 and |40 can be ignored, especiallyby comparison with the fuel ejective effect of the pressure due to theconvcntional fuel pump. This pressure is about p. s. i. in most vehiclesand is capable of being very accurately predetermined and of remainingaccurate over long periods of service in practically all modern fuelpumps. It is also contemplated that even better results than aredescribed below herein will be obtained if, when the carburetor of thisinvention is installed, the usual fuel pump spring is replaced by onewhich increases the fuel pump pressure to a maximum safe value for thefuel system of the particular automobile in'question, in order to takethe fullest advantage of the benefits of the present invention. It islikewise probable that when use of the invention becomes general, fuelsystems having slightly higher safe pressure values will also beinstalled to put the invention to its fullest use.

The liquid fuel under pump pressure, when forced through the tinyorifices at jet |08 or jet |40 or both, is thoroughly broken up intoexceedingly minute droplets and reaches a high state of atomization inthe auxiliary aircurrent which retains for the most part its gaseousform and issues into the main air stream at ports 16. The fuel mixturewhile still in the auxiliary path is, of course, excessively rich, butwhen diluted by mixture with the main air current A, it assumesapproximately the desired 15 t0 l ratio under most circumstances and isthen readily usable by the engine. While, because of their size andnumber, no restriction in area occurs at the openings 16, it should benoted that the sudden deviation in path together with the break-up ofthe flow into a plurality of small streams results in the further andpractically complete atomization of any possibly remaining droplets ofliquid y pressure probably insures a high vaporization rate of any tinyliquid fuel particles which might remain suspended in the stream.

From the foregoing description it can be seen that since the rate offuel emission from the jets is not under the control of the air streamas in the ordinary suction nozzle corburetor, provision must be made forincreasing fuel flow as the main air stream A increases in speed. Thisspeed-up of both air streams occurs in response to increased speed ofthe engine which is brought about by opening the throttle valve 34 as inthe ordinary carburetor. Enlargement of the orifice between jet |08 andmetering projection |22 occurs in concert with the opening of throttlevalve 34 which controls the air flow due to its interconnectiontherewith by sleeve 48, worm 56, sleeve 42 including worm wheel 46 andgear 44, rack member |30, |32 and operating rod |06. The orifice |68,|22 consequently sprays more liquid fuel under fuel pump pressure intothe auxiliary air stream. Since the auxiliary air stream is travellingat a proportionately faster rate as determined by the speed of the mainair stream, its mixture value remains about the same, and the finalmixture with the main air stream also retains its designated fuel-airratio. The foregoing remarks, of course, apply to a deliberate advancein throttle opening where no sudden changes are involved and runningmixtures are called for rather than maximum power.

Acceleration When we modify the preceding state of facts to the extentof opening the throttle rapidly with the intent of developing smooth,quick acceleraopened when i: no '-longer needed.

ztion o'f uthe iengine, fafdifferent :state ofiaiairs f-is aobserved.lively ithrdttle `opening :normally irdoesnot causefimmediateincreaseiinl-air velocity shecause time: isrirequiredlor `the-:engine:to receive `its :added charge rand to speed fup. :At 4:ordinaryifulliezconomy mixtureifand :undenload:thissspeedyup :can only :take:place sratherislowly, so that a `zfull zpower mixture, *substantially:richer than mrdinary, is required :duringithe accelerating n-'tervaliforsatisfactory performance ain this rerspect.Whereasithis'exigencyisztakengcareiof :hy automatic :pumps or:self-emptying :wells in :the msualcarburetonn'o suchexpensiveiccmplication .of theistructure isifoundrnecessary in thedevice of this invention. It will .be notedithatga wideopenpositionpfgthrottle 34,alsocopens the main jet orifice |08, T22 `to itsfullest extent. Inasmucna'sr neither.t air path has .Aasyyeti beenfspeeded .zupsthei fuel :ejected-z iszmuch ihigheriinj proportionitoitheairzthan .ordinarily softhatzthe auxiliar-y air`,path-'mixtureianclitheiinal mixturezare both eniriched substantially.fbeyond normal ,condition :and hence giveffull-:powerandrsmoothfaccelera- "tion :performance Furthermore, `ithe degree -ofthis enrichment, proportionedfalmost vexactly nto -lthe dilerence ibetween present speed-and the terminal fspeed "corresponding vto fthethrottle l'openin-g so v.that .the fenriching effect is .promptlyidecreasedtas ,speedgpicks up; and,promptly termif nated asdesiredlvelocity nis lreached lgiving., just the ilexpenditure :of :fuel`needed-,for i proper, per- .Lformance with .none wast-ed i in :periodstof .frich :mixture production when: therei is; in fact; node- :fmandztherefor.

LStarting *aww-idling Difficulties with starting uunderaordnary `fcarburetion,x and attendant,damagingA effects on the engine canbelaiddirectly at vthe `door of the iusualrstnan'glerior choke valve. rSinceithe :crank- .ingsspeed ofi thei zengine isrextremelyrsloyw.corretspondingfainspeedzinithexusual:carburetor-.throat.1:isninsuilicientto: .drawxoiT-renough I fluid .fuel from thenczzlefto-bring fthefsmixture ratio .fupz 11o-,firing -valuaf or :rat: anyrate, -zthe ,ilu-id, .'fuelvlin =,the air stream isi-:so;-poorlycbroken@upgdue to flow-air r'speediand fa '-coldfmaniiold; :thatthefeectiveA mix- @tureV ofthe/gaseousl portion fofthe :chargefwhen Vitreachesrithe::cylinder-:is: signicantlyabelow :comthustifbleproportions.:'Iloxcorrect this, it is -a-lmost universal to employaifchokerfor,stranglersyawe -Which closes off or restricts the airstream: ahead Y of the fuel nozzleandlhence appliespall or av por-`tionwofthe static engine depression'directly to the fueljet todraw offay higher' proportion of .i liquid Ifuel. With lmore droplets present.to yaporize, the truly gaseous portion of themixfturescanlbe':broughtnup: =to. combustion value; ali. though thefactualfweightVratioof the fuel present -to the air present is much higher than theappron priate 1 to 15. VThis is manifestly a wasteful prof cedure, butcan lbe'tolerated'if the choke adjustnment isprop'erlyvtended and thechoke valve Since the manual adjustment is ticklishand bothersome, itiiisfsimpler for the'operator: to leave it rich long after` vit -isneeded, -f with consequent' `fuel waste, Twashing down of'cylinderWall-lubricant, and :dangerous Adilution of the crank casecontents.`Most'vrnodern carburetors attempt to'avoid this --waste and` potentialengine damagebyencumber- .ing the choke valve `with superimposedautomaticrcontrols-which 'frequently give trouble and failU-to functionproperly. The foregoing waste, @damage-:and-inconvenience is obviated'bythe- 4 1'0 `.present :invention wherein-.no choke valveat all present,and nonezisneeded. Startingposition ,of fthe .carburetor is vmerelythat `in which :the i'throttle valve 34is ,closed asfar as possible`with stop screw 68 .againstthe boss 24. Under these circumstances V,the;main :jet 58, l2`2 is closed and little ifiany ifuel .is allowed topass there- :through .even under ifuel pump pressure. In this-connection it should .be `noted ithat the spring l pressure of spring118, even :though `not particuilarly'heavyis.suicient tosubstantiallyseal the -opening'in jet L08 due to the verysmall taper ofthe` sealing-portion of the metering projection :ii-22. Fuel induction,therefore, ,is effected-mainly through `then-exceedingly :minute .orice.at :the idling ,jet .14.0. While it ,is conceivable ,that -:idling jetf, |40could1berdispensed Withand means provided for adjusting'theminimumopening of jet |08 as a substitute therefor, the structure shown isregarded as more practical in many .,respects, :and is described indetail as .the .pre- ,ferredformJ ,-Normallythe setting of this'` ori-.ce between jet M0 and needlevalve I .42 issuch ,as to cause a mixturejustequalto or slightly richer thanthe most economical settingipossible:for the. air speeds involved at idling speedof the engine. When .theengine is to be started,;of course, v,the f cranking speed and induced.air speeds in themainand auxiliar-yair pathsare substantially .less.than at idling speed so that, `assuming fulLfuel p umppressure, the-mixture -fedto the cylinders ,would be much richer than the ordinaryeconomical-mixture. There maybe `^eertaintendencies. such ase-pulsatingof the fuel pumpat slow ,engine speeds, or an instantaneous .laginvfuel,pump pressure build-up Whichrwould freducep-fuel outputat the .jetldfor yjust VVamo- `ment,-wherel oy the mixture lWouldlce leaned to idealcombustion ,proportions b ut f,vvhei-,her this -`occurs -or not therange Vof-,mixtures which-the yjetM10-.causes to Yexist vin `theintakemanifoldis ,never such as to,preventringvofthe,engine, for:initialii'lringcan occur Veryreadily over a wide `range-of mixturesfromjust slightlyleaner `than 45,ideal running mixture to quite rich. Oncethe A,engine has caught, the mixture present `is-in- ,-stantaneouslyadjusted-*to proper idling value .by theV pick-,up in. airspeedrvthrough bothv air, paths, which vfinally steadies -down at .thespeed for vv,which the output-of the orifice at jet M0 Vis :accuratelyset, andthe mixtureis thereafter aul tomatically taken care of Without:attention 'by .the operatorY and-without anyv of the` complicatedcontrols `normally .considered desirable forthe pstartingoperation.-Sincemixture control is in- ,-stantaneousonce the engine is started itwill be seen-,that there is no,fuel waste due to the long perodiofoperation ata rich mixture Y setting -fwhich yso -often occurs -with theconventional manual choke. Furthermore the1 full atomizing etfectofthepump'pressure atiet itlitogether ,Withtthebreak-up and deection ofthe auxiliary air `current-atV orifices-1,6 `brings aboutsubstanz'tialily: complete subdivisionl of the` uid fuel, as in G5xordinaryrunning, in. spite of the relatively-slow airspeed through thecarburetorunder cranking .and :idling conditions For `this reason the:,danger, fever-present. in .conventional carburetors `.offlooding'the-engine vwith fluid fuel droplets -;Whichf,soenrich-subsequent charges as topre- .vent'starting is practically'obviated `Likewise danger to-cylinderV Wallsand crankcase lubricant.due towtheccleaning fand-.thinning effects `of. the fiuelwhen in fluidform -is-almost entirely avoided. @It should-also benotedf-thatlthedegree ofatomization which the carburetor of the presentinvention effects is such that the temperature of the intake manifoldloses much of its significance with respect to starting, and the enginewill idle properly immediately after starting cold due to the fact thatthe Weight of fuel employed is taken full advantage of. Another way ofexpressing this same condition is to state that the apparent mixture(overall weight of fuel to overall weight of air) is substantially equalto the effective mixture (the ratio of the weights on the basis of thepart of the fuel which is in substantially gaseous state and henceusable). Thus the necessity for the operator to tend the apparentmixture by a choke or strangler valve, or the necessity for complicatedautomatic controls governing the apparent mixture during warm-up idlingis obviated.

Flatspot correction In the development of the carburetor of the presentinvention it was found that with the structure substantially asillustrated in the drawings, but lacking the conduit 98, 94, 96,substantially all of the foregoing features of operation were present.The only readily detectable difference from the model as shown in thedrawing was that the response to accelerator operation was sluggish andunfavorable at a medium throttle setting corresponding to a car speed ofabout 30 M. P. H., but was proper at all other speeds. Even then thisfiatspot could be adjusted out by a resetting of the mixture controlscrew 56, but with some slight reduction in fuel economy at otherspeeds. Certain conditions existing in the ordinary suction nozzlecarburetor wherein there is usually a transfer of the fuel emission froma pilot jet operated either by static engine depression or by air flowat the edge of the throttle, which drops oif from maximum to zero, to amain jet operated by kinetic depression due to air flow past the nozzlewhich picks up from zero and increases to a maximum, are usuallyconsidered to be responsible for a flatspot when the pilot operation isnot sufficiently extended, the main jet is too long in coming fully intoaction, or both. Since the only structure corresponding to a pilot `ietin the present device, namely idling jet |40, |42 is fully operative atall times, no similar cause for the flatspot obtains. One theory whichhas been advanced and which appears to provide a possible explanationfor the iatspot is that the geometry of the auxiliary air path 90, 86,84, 80, 14, 'I6 is such that a certain air speed within the range of airspeeds employed sets up a material vibration of the air column in saidpath, or some significant portion thereof. This vibration may havelimited the flow through the auxiliary path and prevented its bearingthe proper relation to the main air stream flow, thus temporarilyleaning the mixture to a degree unsuitable for brisk performance.

Whatever the cause of this phenomenon, it was found that by merelyproviding a constricted passage connecting the end of nozzle tube 14with the main air stream at a point which lies at the other side of thethrottle valve 34, the conditions were sufficiently changed to correctthe atspot condition described even using the mixture adjustment ofscrew 56 which is the best for economy in all ranges. As previouslydescribed the fiatspot correcting conduit consists of the passage 98,94, 96 and is of materially reduced cross section so that little if anyof the fuel mixture ever reaches the main air stream by way of orifice|00 even when the throttle is in idling position, and its functionappears to be: merely to correct the condition which produced theimpedance in the auxiliary air path resulting. in the flatspot, possiblyby so changing the geom-- etry of the auxiliary air path that thevibratory response if any is displaced to an air speed out-- side of therange employed. Other forms of thev flatspot correction conduit are alsosuitable and it has been found, for example, that a small readilybendable tube of copper or the like attached to the body |0 by the usualtube fittings may be conveniently and successfully used in place of thepassage consisting of drill holes 98, 94, 96 in the boss 24.

Economy of operation Tests have been run by operating the sameautomobile with conventional stock carburetors in good condition, andthen with the carburetor of this invention. Where the maximum ehiciencyattainable with the particular vehicle selected was found to be 18 milesper gallon with the stock carburetor during any extended periodi ofrunning under average conditions, the best efficiency attainable withthe carburetor of this; invention on the same vehicle for a similarperiod of average operation has been found to be 261 miles per gallon,and in no case has the efciency been found to drop below 22.75 miles pergallon for any extended period of running even though some severeupgrade tests may have been included therein. From the foregoing guresit can be readily calculated that the fuel saving effected is 20% at theminimum and would normally be significantly more, up to 30% beingpossible, and 25% being a safe average.

Adaptability to varying applications It has been found that thecarburetor of this invention is extremely adaptable with very minorrevision. The only alteration necessary to provide for use withdifferent types of engines, or to modify the economy-performancerelationship in most respects is a tailoring of the metering projectionof the metering member to suit particular conditions. In fact a widevariety of such metering members may be made in quantity and carried instock for experimental purposes, since the same are readily replaced byanyone capable of removing the cap screw ||6.

In Figs. 6 to 8 are shown three types of metering members illustratingthe manner in which the contour may be altered to provide for variousconditions. Fig. 6 is merely the member |20, |22 which is shown in Figs.3 and 4. This member is designed to give fuel economy within the rangestated above, and which provides for the best average type ofperformance with top vehicle speed and best full power mixture at fullthrottle due to the second slightly sharper tapered tip portion |22 b.Fig. 7 represents a simple metering member |20, |22 wherein the meteringprojection |22 has a single taper of about 1 (similar to the taper ofportion |22a in Fig. 6). This member gives slightly reduced top speedand slightly reduced power at full throttle as compared. with. themember of Fig. 6, and provides for a moderate increase in fuel economy.Fig. 8 shows the general contour of a metering member |20, |22 in whichthe metering member has a form of particular value in connection with afuel pump pressure lower than average, e. g. about 2 p. s. i. While thefuel pressure will normally be adjusted rather than the meteringprojection changed; the pressure vbeing .zpreferablyfnp. s. l. orhigher, the7structure in:Fig f'8'serves1toillustrate how this factorrmay` be readily compensatedfor vif inecessary; The tprojection:|2225",v in additionr to ai regular taper, has azslight. flare at the`top of its' operatingfportion which :causes the initial 'orifice'vopening to rincrease rapidly Which:Y compensates r forthe Ldecrease'df': fuel imipetus produced by the fueltv pump. Otherimeterfinglfmembers, notishovvnprmay be :madey using slightly differenttapersfor use with? engines having 'different displacements, and :still othermeteringmembers'may befspecially devised having even more complexcontoursif :desiredto :K )rocluce-den sired: changesv A,nperformance oreconomyv over anyportionof the operatingrange.

Fig; 9 'illustrates a;slightly Imodifledtform :of the invention whereinall partsvvhichfare the same as inprevious' views .bear the `same:reference characters and thosewhich have correspondence 'to previouslyn described, parts 'bear `the same :refer` ence :characters "primed,"The tbody. 'l andrboss 22' `are slightlyfmodied fini thatno provisionYfor therackl30 is requiredjat onesidefof the throttle shaft32. The'sleeveflizhas been replaced-by; a sleeve t2 which4 is .the/same-exceptfor having thetcam 44" inlzplace yofgear. 44.-: A'folloWer 130';slidesnin borel02, restsonftheearn-IHC andreceives fupon .its upperfsurface therthrust zof operating rodvlilli.A Thevcanfrllri`shownisin-fFig. 9 is :a straight. line fcam* giving affixed rise-,per:de-v gree :rotation of: :theyshaft '32, and the 'operation ofittheidevice is. inrall..respects'the-same as-the device of Figs. 3 andr4. t While tailoring` ofthe surface of cam; 44"; isxaepossiblemethodffor modifyin'gA zthe operation-A -of the'` carburetonit is notpreferredasince lthe t use pf interchangeable 'meterv ing members, orthe-preparationuoffany special contour of metering member as previouslydescribedds .much less cost1y morelexpedientrand accurate and isconsequently the form at present preferred;

From the foregoing description it can be seen that .this inventionprovides a carburetor offer.; ceedingly-simplified constructionr andwhich;` due to- .the particular featuresv above pointedf out',t Viscapable ofY directly -usingandrapplying fuel-pump pressuresHto thecarburetion-ofithe uidfuel, whereby. improved performancecharacteristics together with markedly increased economy Iareachieved.,i

Variations. and modifications may be made withinthe scope of. the claimsandf'portionsof :the improvements. may .beusedwithout others.

l:V A.carburetor comprisingemeans providingzfa main air supply path forconnection with the intake manifold of `anfinternallcombustion engine;additional means providing an auxiliary air path" connected inparalleliyvith said main path, said additional means including an airscoop'extending into said main air path and opening in a directionopposite to the normal direction of air ovv therein, and a tubeextending across said main air path and having a plurality of aperturesformed therein; two fuel emission orifices, one of which is variable,opening on said auxiliary air path; means for supplying liquid fuelunder pressure in excess of atmospheric to said orifices; a movablethrottle Valve for controlling the flow in said main air path; and meansfor varying the size of said variable orice in accordance with theposition of said throttle valve including means for adjusting therelationship of the orice size to the throttle position.

2.1 A'carburetor comprising .atubularfshellhaxY ing` aailange: :at .oneend; for r'connecton: to-"fthe intake manifold :of Van*mternalcombustion engine; an .integral boss :,'oncthe outside cofV=said:;shel1;. :a throttle valve for opening andufclosingsaidtube nearcnet end L and having s: an; operatingf'; shat mounted :forrotationrronfsaidfshell; said :b'oss t be-f ingsapertured :to ;receive.;one fend. of: Lsaidrsh'aft; a" nozzle member -mounted finnsaiclboss.;an'd ,exe tending into the interior of the-shelllatanfinteremediate :point in :its flength; an air- .scoop extending from saidy.bosssinteriorly of saidrfsh'ellx anear the other `end. thereof .'andrinafdirectionz'opening away from :said kthrottle r-valve, said. boss:being provided vvith anf air passage connecting said` air scoop and'said' nozzle; meanson..saidzbossffor makingconnection with the foutput.line ofafcoIr-P ventional 4motor 4vehicle -fuel pump; saidfboss haveingformedthereinra fuel passage connecting;said pump connection:` meansdirectly Withi saidrf-air passage; means i carried 'by saidrboss for#variably Irestricting saidfuel passage;Y andrfmeans carried bysaid bossand mechanically connected With said "shaft -forrcontrollingtheoperationof said'restricting means as 1an. incident tofmovee ment of'said/throttle valve.

3.' A- carburetor comprising a tubular shell hav-- ing'af'ange atoneendffor connection toLthe take manifold of an internalfcom'bustionengine; an integral 'boss on-theoutside Iof 'said shell?" a throttleAvvalvevfor'opening fand= closing-'said 'tube near one end and havingVVanoperatingrshaft mounted for rotationon saidfshell, said boss beingapertured'to receive one endof-"said-y shaft; a nozzle member mounted insaid boss and extendf ing into the interior of the shell at'an'intermedi-1 ate point in itslength'; an airscoop;extending from saidVbossinteriorly of saidi shell :near "the other end-'thereof 'and inadirection opening away from said throttle valve;=said bossbeing-,provided with' an *air passage-fconnectingf'said iairl scoop and"said `nozzle; means =on "said boss for making connection With theAoutput line of: a conventional motor vehicle fuel pump, said bosshavinghfdrmed therein a fuel'duct ileadingfrom'saidfpump connectionmeans, andhaving a straight boreintersectingf saidffuehduct, said airpassage `and. 'said shaft receiving=aperture;l a-fuelf v-jet "inf saidbore between' the -fuel duct Vand 'the lair passage; a meteringeelementslidable-.in said'bore and having a projection cooperating with =saidjetfor-pro viding Y avrvariabl'e lorifice vand ioperatingl lmeans slidabl'einfsaid bore; in contact with said meteringelement Iand *actuatedby=mechanism on said shaft-for enlarging and irestrictingfsaid orificein response to rotation-ofsaid shaft.'

4;- A-vV carburetor -comprising f a tubular shell having alange at-one-r end v"for lconnection to the intake `manifoldiof` 'an internalcombustionfen' gine:l an= integral-boss 'on-the'outsideof said Shell;

a throttlefvalve-foropeninglandfclosingfsaid tube near one end andhaving an operating shaft mounted for rotation on said shell, said bossbeing apertured to receive one end of said shaft; a tubular nozzlemember mounted at one end in said boss and extending across the shell atan intermediate point in its length; conduit means connecting the otherend of said nozzle member with the interior of the shell at the endbeyond said throttle valve; an air scoop extending from said bossinteriorly of said shell near the other end thereof and in a directionopening away from said throttle valve, said boss being provided with anair passage connecting said air scoop and said one end of the nozzle;means on said boss for making connection with the output line of aconventional motor vehicle fuel pump, said boss having formed therein afuel passage connecting said pump connection means directly with saidair passage; means carried by said boss for variably restricting saidfuel passage; and means carried by said boss and mechanically connectedwith said shaft for controlling the operation of said restricting meansas an incident to movement of said throttle valve.

5. A carburetor comprising a tubular shell having a flange at one endfor connection to the intake manifold of an internal combustion engine;an integral boss on the outside of said shell; a throttle valve foropening and closing said tube near one end and having an operating shaftmounted for rotation on said shell, said boss being apertured to receiveone end of said shaft; a tubular nozzle member mounted at one end insaid boss and extending across the shell at an intermediate point in itslength; conduit means connecting the other end of said nozzle memberwith the interior of the shell at the end beyond said throttle valve; anair scoop extending from said boss interiorly of said shell near theother end thereof and in a direction opening away from said throttlevalve, said boss being provided with an air passage connecting said airscoop'and said one end of the nozzle; means on said boss for makingconnection with the output line of a conventional motor vehicle fuelpump, said boss having formed therein a fuel duct leading from said pumpconnection means, and havifng a straight bore intersecting said fuelduct, said air passage and said shaft receiving aperture; a fuel jet insaid bore between the fuel duct and the air passage; a metering elementslidable in said bore and having a projection cooperating with said jetfor providing a, variable orice; and operating means slidable in saidbore, in contact with said metering element and actuated by mechanism onsaid shaft for enlarging and restricting said orifice in response torotation of said shaft. p

6. In a carburetor, means providing a main air supply path forconnection to the intake manifold of an internal combustion engine;moderately restricted conduit means connected at two points with saidmain path and constituting means for providing a parallel auxiliary airpath between two locations in said main air path; a throttle valve forcontrolling the flow in said main air path, located therein to one sideof said auxiliary air path; highly restricted conduit means connectedbetween that portion of the auxiliary air path from which air isreturned to the main air path, and the main air path at the other sideof said throttle valve from said auxiliary air path; and means fordischarging liquid fuel under pressure in excess of atmospheric into theair flowing in said auxiliary air path.

7. In a carburetor, a tubular shell; a small laterally apertured tubeextending transversely across said shell; a throttle valve for openingand closing the passage in said shell at one side of said tube; an airscoop entering the passage in said shell on the same side of thethrottle valve as said tube with its opening directed away from saidthrottle valve; conduit means connecting said air scoop with one end ofsaid apertured tube thus constituting means for providing a parallelauxiliary air path between two locations in said shell; restrictedconduit means connected to the other end of said tube and to theinterior of said shell at a point located on the other side of saidthrottle from said apertured tube; and means for discharging liquid fuelunder pressure in excess of atmospheric into the air fiowing in saidauxiliary air path.

8. In a posterior throttle carburetor, a frame providing an air passage,a jet on said frame opening on said air passage for admitting fluid fuelunder pressure into said air passage; a metering element disposed insaid jet and slidable therein for varying the effective orice thereof; athrottle valve shaft rotatable on said frame; means connecting saidthrottle shaft with said metering member for controlling the positionthereof in accordance with the rotative position of said throttle shaft;and a readily accessible adjustable connection between said shaft andsaid means for adjusting the effective orifice of said jet with respectto a given position of said throttle shaft, said adjustable connectioncomprising a worm rotatably connected with said shaft, and a worm wheelmounted concentrically on said shaft in engagement with said worm andincapable of rotation with respect to said shaft except in response torotation of said worm.

References Cited in the flle of this patent UNITED STATES PATENTS NumberName Date 1,658,484 Ensign Feb. 7, 1928 1,961,775 Mills June 5, 19342,035,636 Chandler Mar. 31, 1936 2,035,681 Udale Mar. 31, 1936 2,150,081Schorsch Mar. 7, 1939 2,225,194 Melcher Dec. 17, 1940 2,247,189 De GuyonJune 24, 1941 2,261,794 Carlsson et al Nov. 4, 1941 2,314,170 SnyderMar. 16, 1943 2,432,283 Chandler Dec. 9, 1947 2,457,765 Winkler Dec. 28,1948 2,462,696 Warburton Feb. 22, 1949 FOREIGN PATENTS Number CountryDate 192,149 Great Britain June 25, 1923

